How to generate T-SNE plots?

I would like to use data from https://portal.brain-map.org/atlases-and-data/rnaseq/human-m1-10x and https://portal.brain-map.org/atlases-and-data/rnaseq/mouse-whole-cortex-and-hippocampus-10x. I am very new to single cell RNA sequencing. I was trying to use Seurat to do the analysis. I started to read the matrix file, its taking a very long time to read this file into R as it is 68GB. I tried using server with 256GB RAM. I would like to know if this is normal. Is there any other better way to do the t-SNE plots (cluster by cell type) with exon expression data for a list of genes?
Please let me know.